You do not refer to the male mamma--which becomes functional once in many million cases, see the curious records of Gynaecomasty. Here practical disuse in the male ever since the origin of the mammalia has not abolished the mamma or destroyed its functional potentiality in extremely rare cases. I absolutely disbelieve in use-inheritance as the evidence stands. Spencer is bound to it a priori--his psychology goes to pieces without it. Now as to the letter. I am no pessimist--but also no optimist. The world might be much worse, and it might be much better. Of moral purpose I see no trace in Nature. That is an article of exclusively human manufacture--and very much to our credit. If you will accept the results of the experience of an old man who has had a very chequered existence--and has nothing to hope for except a few years of quiet downhill--there is nothing of permanent value (putting aside a few human affections), nothing that satisfies quiet reflection--except the sense of having worked according to one's capacity and light, to make things clear and get rid of cant and shams of all sorts. That was the lesson I learned from Carlyle's books when I was a boy, and it has stuck by me all my life. Therefore, my advice to you is go ahead. You may make more of failing to get money, and of succeeding in getting abuse--until such time in your life as (if you are teachable) you have ceased to care much about either. The job you propose to undertake is a big one, and will tax all your energies and all your patience. But, if it were my case, I should take my chance of failing in a worthy task rather than of succeeding in lower things. And if at any time I can be of use to you (even to the answering of letters) let me know. But in truth I am getting rusty in science--from disuse. Ever yours very faithfully, T.H. Huxley. P.S.--Yes--Mr. Gladstone has dug up the hatchet. We shall see who gets the scalps. By the way, you have not referred to plants, which are a stronghold for you. What is the good of use-inheritance, say, in orchids? [The interests which had formerly been divided between biology and other branches of science and philosophy, were diverted from the one channel only to run stronger in the rest. Stagnation was the one thing impossible to him; his rest was mental activity without excessive physical fatigue; and he felt he still had a useful purpose to serve, as a friend put it, in patrolling his beat with a vigilant eye to the loose characters of thought. Thus he writes on September 29 to Sir J. Hooker:--] I wish quietude of mind were possible to me. But without something to do that amuses me and does not involve too much labour, I become quite unendurable--to myself and everybody else. Providence has, I believe, specially devolved on Gladstone, Gore, and Co. the function of keeping "'ome 'appy" for me. I really can't give up tormenting ces droles.